1. Technical Field
The present invention relates to expandable shoes that may be adjusted longitudinally.
2. Discussion of Related Art
Some attempts have been made to provide expandable shoes, which can purportedly withstand day-to-day use. U.S. Pat. No. 3,389,481, for example, discloses a shoe in which a two plate assembly is disposed between an inner and a disjointed outer sole, having overlapping front and back portions. One of the plates includes a spring tongue, and the other plate includes two apertures to receive the spring tongue, each aperture corresponding to a shoe size. To adjust the shoe size, a screw which extends through the heel and into the disjointed soles is removed. The shoe may then be pulled apart allowing the disjointed sole to separate until the spring tongue engages the next aperture. Thus the shoe size may be lengthened by one size, but apparently the size cannot be controlled finely or reduced. The shoe includes two crinkled leather portions 34, one on each side of the shoe, to facilitate expansion of the shoe.
WO 01/33986 describes an expandable shoe. The expandable shoe includes an outer shell having a front and a rear outer assembly each attached to a flexible, expandable segment. An adjustable inner assembly is disposed within the outer shell and includes a control mechanism, accessible from the outer shell, that may be urged from a lock state into a state in which the inner assembly and outer shell may be adjusted. A visualization window provides a view port to the inner assembly.
Though WO 01/33986 details a desirable expandable shoe design, certain improvements thereto have been discovered to improve ergonomics, torsional rigidity, handling, and the construction of the shoe.
Under one aspect of the invention, an expandable shoe is provided which includes a front outer assembly, and a rear outer assembly. An expandable segment attaches to the front and rear outer assemblies to define a shoe outer shell and the expandable segment extends at least partially along each side of the outer shell and transversely across the bottom of the outer shell. An adjustable inner assembly is disposed within the outer shell and has a first board portion and a second board portion in overlapping engagement with each other. The inner assembly also includes a control to adjust the position of the first board portion relative to the second board portion and to thereby adjust a dimension of the inner assembly and thereby a corresponding dimension of the shoe.
Under another aspect of the invention, the control includes a locking mechanism shaped to engage and hold one of the first and second board portions, a biasing mechanism to bias the locking mechanism into engagement with one of the first and second board portions; and an urging member having a proximal portion external of the shoe outer shell and positioned and movable transversely to a longitudinal direction of the shoe and in transverse alignment with the locking mechanism.
Under another aspect of the invention, one of the first and second board portions include transversely extending teeth, and the locking mechanism includes transversely extending teeth and the urging member include a rod portion having at least two diameters. The locking mechanism includes an aperture in alignment with the rod portion and the cross section of the aperture is larger than the smaller of the at least two diameters but smaller than the large of the at least two diameters. When the urging member is moved, the rod portion contacts and moves the locking mechanism with the larger of the two diameters.
Under another aspect of the invention, one of the first and second board portions includes an upward-facing cavity containing the control. The opening to the cavity is covered by the other of the first and second board portions when the first and second board portions overlap.
Under another aspect of the invention, one of the first and second board portions includes at least one groove extending longitudinally and the other of the first and second board portions includes a corresponding rail in alignment with the groove. The rail is positioned within the groove as the first and second board portions overlap.
Under another aspect of the invention, one of the first and second board portions has at least one projection which extends into a cavity in the sole.
Under another aspect of the invention, at least one of the first and second board portions includes a lattice support structure.
Under another aspect of the invention, one of the first and second board portions includes a set of notches and the locking mechanism has a surface feature to contact a notch in the set of notches to resist relative movement of the first and second members in relation to shoe size and provide ergonomic sensation.
Under another aspect of the invention, a visualization window provides a view to the inner assembly. The inner assembly may include size markings or other indicia representative of a shoe adjustment, and these markings may be placed on the inner assembly to allow them to be visible through the visualization window.
Under another aspect of the invention, a light source may be provided in the cavity to illuminate the visualization window.